1. Field of the Invention
Embodiments of the present invention generally relate to systems, apparatus and processes for gasifying a hydrocarbon. More particularly, embodiments of the present invention relate to recovering and processing waste gas in a gasification system and/or process.
2. Description of the Related Art
The practice of producing electricity, syngas, ammonia, urea, and/or other products from a carbon-containing feedstock using various gasification processes is known. Typically, the carbon-containing feedstock, which can be natural gas, coal, biomass, organic waste, and/or the like, is fed to a gasifier. In the gasifier, the hydrocarbon can be pyrolyzed to create a carbonaceous char. Oxygen and/or steam can then be introduced into the gasifier at high temperature and can react with the carbonaceous char therein to produce raw syngas. The raw syngas can include varying ratios of hydrogen gas and carbon monoxide, along with methane, carbon dioxide, water vapor, and other constituents such as ammonia, nitrogen, hydrogen cyanide and the like.
The raw syngas produced in the gasifier is often further processed and purified to produce a usable syngas product. Conventional processing and purification can include shifting the syngas to convert carbon monoxide to hydrogen gas, removing carbon dioxide and/or sulfur, and/or purifying to remove other undesirable components from the raw syngas. Purifying can result in a waste gas, which can include valuable hydrocarbons, which is typically burned as fuel to help drive the gasification process. What is needed are efficient apparatus, systems, and methods for recovering and reforming the rejected components of the waste gas into additional syngas, instead of, or in addition to, using the waste gas as fuel.